For WPPD 2013 we went over the top! This was designed to use standard 8x10 filmholders after acquiring two holders in good shape at a decent price via eBay. The larger formats tend to produce the most impressive pinhole results. Unfortunately 8x10 film is brutally expensive, so we planned to go with paper negatives for the first outing.

This camera is based on a wooden frame using an odd cross-section cut from a piece of 1x4 oak. The rear edges are milled with a large rabbet to locate the filmholder. The front edges are designed to receive 1/4 inch plywood at a 45º angle. A pyramidal "nose cone" was fabricated to fit that, closed off by a rectangular slab to carry the pinhole plate and shutter mechanism. A scary exercise in compound miters.

As with the 4x5 version, large rubber bands over wood pegs keep the filmholder against the foam-gasketed back. Some short 1/8 inch diameter pegs provide a reference to permit aiming the camera by sighting along the pegs. (An experimental frame viewfinder for the 4x5 proved to be fairly useless because of the wide angle of view.)

One shortcoming noted after field use: It would be nice to have a handle of some sort. In the workshop during construction, one could easily grab the beastie by the edge of the open box. With a filmholder in place,it is rather awkward to handle, especially one-handed, if switching cameras via the tripod quick release.

The final parameters:
Pinhole to film distance ("focal length"): 6.0 inches (153 mm)
Exposure Mask Area: 8.0 x 9.7 inches (203 x 246 mm) Diagonal: 12.6 inches (319 mm)
Diagonal Field of View: 92º
Pinhole diameter: 0.022 inches (0.56 mm); about f/275
Pinhole Constant: 1.65
f/22 Exp Multiplier: 154
Weight (Rev 1.1): 2.34 Kg (~5.2 lb) with filmholder

The 8x10 Pinhole camera was first used for WPPD 2013.
Later in May we did Rev. 1.1 by adding a wooden handle and also a swing-out foot to enable the camera to rest upright.
The camera was used again from 2014, and continues to be used each year thus far.

In April 2017, having discovered a crack in the brass shim stock for the original pinhole, Ye Olde Photographer made a new one. It is a bit larger in diameter, but still made by 'dimple-and-sand' in 0.001 inch stock.
The new pinhole:
Pinhole diameter: 0.025 inches (0.635 mm); about f/250
Pinhole Constant: 1.90 ("Rayleigh")
f/22 Exp Multiplier: 129
Gut sense, based on 2017 results, is that going larger was the wrong direction!

In 2018, being somewhat disappointed in the 2017 results, a new pinhole was fabricated in 0.002 inch brass with a diameter of 0.020 inches.
The 2018 pinhole:
Pinhole diameter: 0.020 inches (0.51 mm); about f/300
Pinhole Constant: 1.75
f/22 Exp Multiplier: 188

See some tests with X-ray film here and some "real photos" on X-ray film in this gallery and in the WPPD galleries for 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, and 2023.